Electric furnace.



J. BALLY. ELECTRIC FUBNAGE. PPLIOATIOI FILED JULY 5, 1912.

Patented July 29, 1913.

A PTV J BALLY.

ELECTRIC FURNAUE.

APPLIoATIoN FILED JULY s, 1912.

m W im M MM j 9% m M a 5.. n E f m 1 W 7n Patented July 29, i913.

ELECTRIC FURNAE.'

APPLIUTION FILED JULY, 1912.

1,068,558. Patented July 29, 1913. ffl G I 5 s Sanna-sum: s.

Patented July 29, 1913.

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J.BALLY.

ELECTRIC FUBNACB.

APPLIOATION FILED JULY 5,-1912.

5 SHEETS-SHEET 5.

IIb II Patentedl July 29, 1913.

UNITED STATES JEAN BALLY, 0F GRENOBLE, FRANCE.

ELECTRIC Specification of Letters Patent.

FURNACE.

Patented July 29, 1913.

Application ledJ'uly 5, 1912. Serial No. 707,854.

Be it known that I, JEAN BALLY, citizen of the Republic of France,residing at 4c Rue de la Fdration, Grenoble, Isre, inthe Republic ofFrance, have .invented new and useful Improvements in Electric Furnaces,of which the following is a specification.l

This invention relates to an electric induction furnace of the typewherein the available energy is directly transformed into inducedcurrents in the furnace by means of a stationary armature formed by themetal or other conducting material contained in the furnace and a fieldmagnet or inductor. One characteristic feature of the invention is thatthe conduits containing the material to be heated are so arranged thatthe axis or center lines of said conduits are all on a cylindricalsurface, the stationary or rotating inductor being located inside ofsaid surface. The stationary armature may thus be formed by shaftsarranged in parallelism with the inductor axis and located in the slotsofa mag-v netic frame, said shafts being connected together by conduitsor plates so as to form a single phase or multipliase structure; thearmature coils which are each formed by two shafts are connected inseries, in multiple or in multiple series and are located upon one ormore cylindrical surfaces having the same axis as the inductor system.This electrical furnace has important advantages which will be pointedout thereafter.

In the annexed drawings: Figures 1 to 3 show diagrammatically invertical section, horizo-ntal section and unfolded view, respectively,an electric furnace constructed in accordance with the invention, themovable inner inductor having four poles. Figs. 4 to 6 are correspondingviews of a furnace with siX poles, the Ashafts having gradually varyingcross sections. Fig. 7 is a vertical section through the axis of a'furnace inwhich the shafts are provided at their upper end withenlargements or working chambers. Figs. 8, 9 and 10 are horizontalsections along the line A-4-B in Fig. 7 showing different types offurnaces with working chambers. Fig. 11 is a horizontal section similarto Figs. 8, 9 and 10, showing a furnace provided with an annular workingchamber and having its armature in the form of a squirrel cage winding.Fig. 12 is a corresponding .horizontal section on the level of the lowerpart of the shafts. Figs. 13, 14: are views similar to Figs. 11, 1Q, ofan electric/furnace with an uninterrupted Working chamber, the shaftsbelng arranged by pairs. Fig. V15 4is an enlarged vertical section alongC-l),

Fig. 17, of a single phase furnace 4wherein f the inductor and armaturehave each eight poles. furnace along the line E-F, Fig. 17. Fig. 17 is ahorizontal section' thereof along the line (St-H, Fig. 15. Fio'. 18shows a vertical section thereof unfgolded in a plane. Fig. 19 is ahorizontal' section of a twelve pc-les furnace for three metals, withthree lcircuits of different capacities, the furnace being formed bythree parts capable of being tipped separately for casting.

The electric furnace shown in Figs. 1 and 2 comprises a number ofvertical shafts 1 formed ina body 2 of lire-proof material. The shaftsl'are designed to contain the metal, ore or other conducting material tobe melted or treated which forms the armature or stator. Said shafts 1are located around a'central circular space 3 in which an inductor lrotates. The inductor 4 is keyed on a shaft 5 which is parallel to theshaft and is' actuated by any suitable source of motive power. Themagnetic frame of the -armature is formed by metal sheets 6 arranged oneupon the other andcut away to receive the shafts 1 which are thuslocated as in the slots of the magnetic frame in an alternator. Thewhole of the shafts 1 and the magnetic frame 6 may be surrounded by acasing 7.

The inductor lis excited in any suitable manner. "-In the constructionshown in Fi s. 1 and 2, the inductor or rotor has four po es and theshafts 1 which form the poles of the armature or stator are valso fourin number. The shafts 1 are in communication fogether i`n series so asto form an uninterrupted electric circuit. As shown in Fig.' they areconnected together alternately at their upper part by means of a channel8 formed inthe upper sui-facer of the refractory body and attheir'l'ower part by a conduit 8 formed in the. interior of said body.The shafts may also be connected in multiple or in parallel or inparallel series as hereinafter explained instead4 of being in series.

Instead of "being of a cylindrical shape and having a cross section ofuniform size lthroughout theirflengtlas/in Figs. 1 to 3. the shafts mayhave av cross section. the size of which gradually increases to ard thetop F ig. 16 is a vertical section of said (Figs. 4 to 6) or they may beprovided at the ytop with an enlarged part 9 (Fig. 7) called workingchamber which p ermits of handling more easily the material to betreated, while leaving to the shafts a small cross section on thegreater part of their length, which is desirable for heating purposes. Afurnace having for instance siX shafts ma be provided With a singleworking cham er 9 or two working chambers (Fig. 9) or as many workingchambers as there are shafts (Fig. 10), the connecting channels 8provided at the upper end of the furnace running into said chambers.

According to Fig. 11, the separate Working chambers above described arereplaced by a circular channel 8b forming an uninterrupted workingchamber. In this case, all the lo-W'er` ends of the shafts may be connected together as sho-Wn in Fig. 1Q, which affords the arrangementcalled squirrel cage Winding. Which may be used either for single fphase of multipliase current. According to Figs. 13 and 14, the furnaceis also provided With a continuous working chamber 8b but the lowerconnections 8 are arranged in such a manner t-hat the shafts aredistrib- `uted into coils each formed of two shafts and connectedtogether in parallel.

If the furnace is intended to work as a three phase' furnace, the twelveshafts are distributed into three distinct phases arranged at suitableangles one to the other. The phases may be connected together pro-Vvidedthat each of them forms an independent closed circuit. Theconnection may b e obtained through a common working chamber. The upperconnecting conduit could be superposed or arranged at various levelsinstead of being on the same plane as shown. The same remark applies tothe lower connections.

The inductor system 4 could be formed if desired by a number ofsuperposed inductors, as Well as the magnetic frame. Two or more shaftscould also be arranged on the same radial line'of the furnace, saidshafts belonging to different concentric circuits and being thereforeunder the infiuence of derivations of the magnetic flux.

The furnace shown in det-ail in Figs. 1K to 18,-is a single phasefurnace with eight polesand vtWo Working chambers. ductor 4 may bedirectly coupled to any suitable engine or actuated otherwise. Therefractory body 2 in which the shafts are formed is contained at thebottom in` annular pieces 11, 12, 13, carried by a base 14 which isYitself supported by any suitable foundation and may be provided withany appropriate device for centering the furnace around the induotoraxis. A metallic shell 7 is arranged around the furnace which is closedat the top by a cover 15 provided with holes corresponding to .theshafts. For

The inclosing the shafts when desired, or in View formed by conduitsprovided in the refractory body. Two of the shafts 1, located atdiametrically opposite points and having an enlarged cross section, formthe Working chambers 9, 9a. The furnace is extended laterally at thesepoints (Fig. 17) so that an easier access may be had to said workingchambers. e

The magnetic frame of the armature is formed by sul'ierposed metalsheets or plates (5. For facilitating the erection and preventingruptures by expansion under the action of heat, said platesmay bedivided -shown into sectors of suitable shape which are in contacttogether by their edge. Each of the sectors has on its edges a bead orridge 1G so as to leave between the superposed plates hollow spaces 17(Figs. 15, 1(5) 1n which a fluid may be caused to circulate for coolingthe arma-ture in its thick parts when it is not desired to utilize toits full extent in the refractory body the heat` produced by hysteresisin the magnetic frame of the armature. In the case of an air circulationthe same is created by the rot-ation of the inductor 4 and a fan not4shown keyed on its shaft. The outer shell 7 is provided with holes 1Swhich may be closed by dampers, said holes permitting the air which has.entered the spaces 17 in the interior of the furnace to escapeoutwardly.

The plates or sheets 6 of the magnetic frame are carried in theconstruction shown by sleeves or tubes 19 mounted on bolts 19a which arefixed at the top in the cover 15 of the furnace. By this arrangement,all the metal parts of the furnace may be erected before the refractorymaterial is put into place. In the formation of the shafts and conduitsin the refractory body, a metal core may be used which may act as aconductor for the preliminary heating of the furnace and is meltedthereafter.

20 is a cent-ral exhaust pipe which extendsabove the furnace for thepurpose of preventing the movable part of the furnace from injury andleading upward the main part of the air current produced by the fan,which air current serves to cool the magnetic frame and also theinductor, the latter beingv also cooled by its rotation in the air. Theexhaust pipe 20 is preferably made in two parts so that the lower partmay be raised for facilitating the raising and tip ping of the furnace.One of the shafts may be provided with a pouring nozzle and the whole`of the armature maybe carried by three or more hydraulic pistons whichallow of first raising the armature to clear the inductor structure andthen tipping said armature.

It will be noted that the upper connections between the shafts 'arelocated at a certain distance beneath the upper ends of the shaftswhereby a large amount of metall may be poured without getting thefurnace out of operation by breaking the electric circuit.

rl`he type of electric furnace above dcscribed has special advantageswhen used for melting o-r preparing alloys. In this case the shaftsand'conduits are arranged so as to form separatecoils or circuits whichmay contain different lnetals or alloys.

For the purpose of making easier the management of the furnace, the samemay be divided into a number of sections 2a 2b 2 (Fig. 19) correspondingto that of the different metals or alloys, the sections being heldtogether in the operation by bands 22. The joints between the sectionshave no influence upon the magnetic. circuits as it will be readilyunderstood. Each section is then provided with a pouring nozzle QC sothat for emptying the section of the furnace which contains thedesiredmetal. or alloy` the bands 22 may be disconnected and said sectiontipped in a known manner. In this case, it is not necessary to raisefirst the furnace above the inductor as in furnaces in one piece. A

The new electric furnace above described either with stationary orrotating' inductor has overthe electric furnaces already kno-wn thefollowing advantages:

1. The capacity of the furnace may be arranged invai'iolis ways and agreat number of different combinations may be realized for instance incombining in the same furnace several systems with dilferent shaftsprovided or not with working chambers, in series, in parallel or inseries parallel, in single phase or multiphase systems, and located inone or more concentric circles, according to the conditions to be met,whereby the furnace may be rendered suitable for industrial applicationsof all kinds.

2. The refractory lining of the furnace is in very good conditions ofresistance, the

parts exposed to the air being reduced to the minimum by the arrangementof the shafts, and the whole being rigidly secured together by themagnetic frame itself.

The heating and melting operations are effected in the best conditionsforresisting to 'the electric phenomena of contraction which can occurin the-parts of the circuits having small cross sections. In the furnaceaccording to the invention, instead of avoiding said strangulatedportions, the same may be used with advantage in the lower parts of heshafts and in the lower connecting conduits either in arrangingajpc-rtion'of reduced cross section or in giving to the shafts a crosssection decreasingl gradually toward the bottom. This arrangement is notobjectionable because o-f the pressure of the metal body which isopposed to the phenomena of contraction. The described arrangement hasalso thel important advantage of facilitating the natural stirring ofthe melted mass in View of rendering the metal more homogeneous, by therising of the' heated parts in the metal mass in the shafts and thesinking of the cooler parts and the charges or additional materialspoured into the shafts.

4. The losses of heat by radiation are considerably reduced, the area ofthe bath exposed to thc air being restricted to the upper ends of theshafts, which maybe closed easily by means of plugs.

5. The ohmic resistance may be easily increased and the self inductionreduced accordingly in view of increasing the power coetlicient.Moreover the melting of highly conductive metals, can be effected moreeasily than in the known induction furnaces ot' the transformer typewith a horizontal channel in view of the greater length which may beeasily given to the circuit in a furnace according to the inventionhaving the samt` diameter by I means of the several shafts.

lla ving now described my invention, what I claim as new and'desire tosecure by Letters latcnt is:

1. In an electric furnace: a stationary armature comprising channelsconnected together which conta-in the material to be heated and arearranged around a central space and an inductor located in said centralspace, said inductor being formed of a number of polar pieces soarranged that the axis thereof extend radially from the axis of thefurnace, substantially as described and for the purpose set forth.

2. In an electric furnace: a stationary ar. mature comprisingsubstantially horizontal and 'vertical channels which cont-ainthematerial to be heated and are arranged around a central space and aninductor located in said central space, said inductor being formed of anuanber of pola-r pieces so arranged that the axis thereof extendradially from the axis of the furnace, substantially as described andfor the purpose set forth.

3. ln an electric furnace: an annular stationary armature comprisingchannels which contain the material to be heated and are arranged arounda central space, an inductor rotating in said central space, saidinductor being formed of a number of lpolar pieces so arranged that theaxis thereof extend radially from the axis of the furnace, and means forrotating and exciting the inductor. sub-v stantially as described andfor the purpose set forth'.

4. In an electric furnace,in combination: an'annular stationary body,devices in said Clt body for containing` ihe material to be heated, saiddevices beingparallel with the axis of the annular body, means forconnecting said devices toggjether, a magnetic frame around saiddevices. an inductor rotating inside the annular body and means forrotating and exciting the inductor, substantially as described and forthe purpose set forth.

In an electric furnace, in combination: an annular stationary body'madeof refractory material, shafts in said body containing the materialto be heated said shafts being parallel with the axis of the annularbody, and havingI a gradually decreasing cross section from the top tothe bottom, Working chambers at the top of said shafts, conduits in theannular body connecting said shafts together, a magnetic frame aroundthe shafts, means for supporting said magnetic frame independently ofthe refractory body, an inductor rotating inside the annular body andmeans for rotating and exciting the inductor, substantially as describedand for the purpose set forth.

G. In an electric furnace, in combination, an annular stationary bodymade of refractory material, shafts in said body containing the materialto be heated, said shafts being parallel with the axis of the annularbody, and having a gradually decreasing cross section from the top tothe bottom, Working chambers at the top of said shafts, conduits in theannular body connecting 'said shafts together, a magnetic frame aroundthe shafts means for supporting said magnetic frame citing the inductor,substantially as described and `for the purpose set. forth.

7. In an electric furnace, in combination: an annular stationary bodymade of refractory material, shafts in said body containing the materialto be heated, annular conduits in the annular body connecting the shaftstogether at the top and at the bottom, respectively, a magnetic framearound the shafts, an inductor rotating inside the annular body andmeans for rotating and exciting the inductor, substantially as describedand for the purpose set forth.

8. In an elect-ric furnace in combination: an annular stationary bodymade of a plurality of sections, removable means for rletaining saidsections together, shafts in said sections, an inductor rotating insidethe any nular body and means for rotating and exciting the inductor,substantially as described and for the purpose set forth.

In testimony whereof I have signed my name to this specification in thepresence of" two subscribing Witnesses.

4 JEAN BALLY. IVitnesses: Louis MosEs,

LUCIEN MEMMINGER.

